Today I was consulted on a complicated patient with an unexplained elevation of the WBC count. In most cases, there is a standard approach to figuring out what is triggering this immune response. It involves searching for sources of infection such as a pneumonia, urinary tract infection, skin infection, or abscess as well as non-infectious causes too.

However, in some cases it is not an easy task.

Today's patient had received a kidney transplant 10 years ago. Transplantation of an organ necessitates severely suppressing the immune system in order to allow the foreign organ to avoid rejection by the immune system. However, immunosuppression renders the patient vulnerable to infections--ordinary and unusual--and often presents particularly challenging puzzles to the infectious disease physician, something we all relish.

My patient was not only immunosuppressed with an elevated WBC count, he also had a cancerous mass on his wrist, likely another consequence of his immunosuppression. The disabled immune system of a transplant patient is not only impaired in its ability to fight infections, but also in its ability conduct tumor surveillance. As such, cancers are not infrequent in transplant patients.

To add to the complexity, the patient was found to have a nodule in his lung. In an ordinary patient, a nodule is usually an incidental finding. But, in a transplant patient a nodule can be the result of myriad big and bad things including unusual bacterial, viral, mycobacterial, or fungal infections as well as cancer. In a transplant patient, the cause of nodules must always be run down lest it cause severe illness (see this excellent review written by my colleagues whom I once trained under).

Pittsburgh, led by the father of transplantation Dr. Thomas Starzl (for whom our transplant center and a street is named), became a city renown for its pioneering work in organ transplantation. Dr. Starzl's memoirs are aptly entitled The Puzzle People. The title refers to the notion of transplant patients as being amalgamations of various puzzle pieces (i.e. transplanted organs) but I also like to think of transplant patients as presenting vexing and intellectually stimulating puzzles to physicians who are forced to think and think again before a solution becomes apparent--an intellectual exercise like no other.